Maho Bay Watersports Center divers reported sighting an exotic invasive Indo-Pacific lionfish (Pterois volitans) in park waters in Leinster Bay near Waterlemon Cay last Monday. The next day, park dive team members Rafe Boulon (chief of resource management), Thomas Kelly (biologist), Devon Tyson (biological technician) and David Horner (protection ranger) searched for and captured the eight-inch juvenile lionfish, found in 40 feet of water just east of the cay. It is the first lionfish caught in National Park Service Caribbean waters, the first caught off St. John, and the 19th caught in U.S. Virgin Island waters.
Biologists fear that the non-native fish will wreak havoc on local fisheries within the park. Introduced lionfish can rapidly become an established species and pose potential problems for both the environment and humans:
They are voracious predators that appear to compete for food resources of the commercially and ecologically important snapper-grouper fishery, which is already depleted.
Female lionfish can produce approximately 2.3 million eggs per year and can grow to 20 inches in length in the Atlantic.
They have few natural predators in the Atlantic Ocean and studies show that Atlantic predators avoid lionfish.
Lionfish are not timid and readily approach divers and snorkelers.
Their venomous spines can sting park users and can cause intense pain, swelling, headache, nausea, paralysis, and convulsions.
Said Boulon: "This is the first problem of many, many more to come, unfortunately."
The park has been distributing fliers warning divers about the dangers the fish poses to the reef ecosystem since last year. The fish is now preserved and has been reported to the national lionfish database. Tissue samples are being sent for genetic analysis to try to determine the route by which the lionfish arrived at Virgin Islands National Park.